How can I get rid of a pimple overnight?

You can't. This won't happen. If the problem is occasional acne pimples, you can usually keep most of them at bay with a salicylic acid face wash. It's not pleasant but is likely to be enough.

Related Questions

How can I completely get rid of pimples overnight?

You can't. Forgive my frankness. Your fastest help will come from topical benzoyl peroxide plus whatever supplemental Rx your personal physician will prescribe for you. There are no quick fixes. You need to manage your acne as a serious chronic disease until it remits on your own. . Read more...